Skip to main content
Glama
Sign In

Marketplace Seller Fee Calculator

by io.github.davidemena-spec
OverviewDiscussionsAdmin

Calculate fees and profit

calculate_fees
Read-onlyIdempotent

Calculate the seller fees, net payout, profit, margin and ROI for selling one item at a given price on one US marketplace, itemized fee by fee from the marketplace's official fee schedule. For Amazon FBA and Walmart WFS, include package dimensions to add fulfillment fees.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "marketplace": "<marketplace>",
      "sale_price": "<sale_price>"
    },
    "name": "calculate_fees"
  }
}

Input Schema

NameRequiredDescriptionDefault
detailNosummary (default) returns totals and fee lines; full returns the complete REST response.summary
optionsNoMarketplace-specific options (e.g. ebay store_subscription, etsy offsite_ads_percent). See list_marketplaces for names and values.
packageNoPackaged unit dimensions (inches) and unit weight (pounds), used to determine the fulfillment size tier, dimensional weight (L x W x H / 139) and shipping weight. Required for amazon_fba and walmart_wfs.
categoryNoFee category; valid values depend on marketplace. amazon_fbm: default, 3d_printers, amazon_device_accessories, appliances_compact, appliances_full_size, automotive, baby, backpacks_handbags_luggage, base_equipment_power_tools, beauty, industrial, clothing_accessories, computers, consumer_electronics, electronics_accessories, eyewear, footwear, furniture, gift_cards, grocery, home_kitchen, jewelry, lawn_garden, lawn_mowers_snow_throwers, mattresses, media, merchant_fulfilled_services, musical_instruments_av, office_products, pet_supplies, pet_veterinary_diets, sports_outdoors, tires, tools_home_improvement, toys_games, video_games_accessories, video_game_consoles, watches | amazon_fba: default, 3d_printers, amazon_device_accessories, appliances_compact, appliances_full_size, automotive, baby, backpacks_handbags_luggage, base_equipment_power_tools, beauty, industrial, clothing_accessories, computers, consumer_electronics, electronics_accessories, eyewear, footwear, furniture, gift_cards, grocery, home_kitchen, jewelry, lawn_garden, lawn_mowers_snow_throwers, mattresses, media, merchant_fulfilled_services, musical_instruments_av, office_products, pet_supplies, pet_veterinary_diets, sports_outdoors, tires, tools_home_improvement, toys_games, video_games_accessories, video_game_consoles, watches | walmart: default, apparel, appliances_compact, appliances_major, automotive, baby, base_power_tools, beauty, books, camera_photo, collectibles, consumer_electronics, electronics_accessories, furniture, grocery, home_kitchen_decor_garden, industrial_scientific, jewelry_precious_metals, luggage_travel, music, musical_instruments, office_products, printer_cartridges, outdoor_power_tools, outdoors_sports, outdoor_optics, personal_computers, pet_supplies, plumbing_hvac, shoes_handbags_backpacks_sunglasses, software_video_games, tires_wheels, tools_home_improvement, toys_games, video_dvd, video_game_consoles, watches | walmart_wfs: default, apparel, appliances_compact, appliances_major, automotive, baby, base_power_tools, beauty, books, camera_photo, collectibles, consumer_electronics, electronics_accessories, furniture, grocery, home_kitchen_decor_garden, industrial_scientific, jewelry_precious_metals, luggage_travel, music, musical_instruments, office_products, printer_cartridges, outdoor_power_tools, outdoors_sports, outdoor_optics, personal_computers, pet_supplies, plumbing_hvac, shoes_handbags_backpacks_sunglasses, software_video_games, tires_wheels, tools_home_improvement, toys_games, video_dvd, video_game_consoles, watches | ebay: default, electronics, clothing, books_media, vinyl_records, guitars, jewelry, watches, handbags, athletic_shoes | tiktok_shop: default, jewelry_precious, jewelry_other, collectibles, pre_owned | etsy: default | facebook_marketplace: default | poshmark: default | mercari: default | depop: default | stockx: defaultdefault
item_costNoSeller's cost of the item, in USD. Default 0.
sale_priceYesItem price the buyer pays, in USD, excluding shipping and tax.
marketplaceYesamazon_fbm = Amazon (Fulfilled by Merchant); amazon_fba = Amazon (Fulfilled by Amazon); walmart = Walmart Marketplace; walmart_wfs = Walmart Marketplace (Walmart Fulfillment Services); ebay = eBay; tiktok_shop = TikTok Shop (US); etsy = Etsy; facebook_marketplace = Facebook Marketplace; poshmark = Poshmark; mercari = Mercari; depop = Depop (US); stockx = StockX (Verified Marketplace)
other_costsNoOther per-item costs (packaging, ads, etc.), in USD. Default 0.
shipping_costNoSeller's shipping label cost, in USD. Default 0.
fulfillment_dateNoamazon_fba only: ship date (YYYY-MM-DD) that selects the FBA rate card. Defaults to today (UTC). Range 2026-01-15 to 2027-10-14.
shipping_chargedNoShipping the buyer pays, in USD. Default 0.
estimated_sales_taxNoSales tax collected from the buyer, in USD (some marketplaces charge fees on it). Default 0.

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A3.8/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint, idempotentHint, non-destructive and a closed-world scope, so safety is covered. The description adds useful provenance and modeling context beyond that: fees come itemized from the official fee schedule, and package dimensions drive fulfillment size tier, dimensional weight and shipping weight, which explains why the tool sometimes needs extra input.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, both front-loaded with the core verb-and-scope then the one non-obvious input rule. No filler, no restating of the title, and the conditional requirement is placed where an agent will hit it before the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 12-parameter tool with a nested package object and no output schema, the description names the computed outputs (net payout, profit, margin, ROI) and the fee-by-fee itemization, which is enough to set expectations about the result. It stops short of describing the summary versus full detail behavior or how defaults for costs treat profit, but the schema carries those details at full coverage.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents the marketplace enum, the detail enum, category lists, and even the 'Required for amazon_fba and walmart_wfs' wording for package. The description's FBA/WFS package note therefore restates structured data rather than adding new meaning, which lands at the baseline 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb and a full set of outputs (seller fees, net payout, profit, margin, ROI) for one item at a given price on one US marketplace, plus the data source (the marketplace's official fee schedule). That scope phrase, 'one US marketplace', implicitly separates it from comparison tools, but it never names a sibling such as compare_marketplaces or find_target_price, so the differentiation is left to inference.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is one explicit conditional instruction: include package dimensions for Amazon FBA and Walmart WFS so fulfillment fees are added. Nothing states when an agent should prefer this tool over compare_marketplaces or find_target_price, and no exclusions are given, so the when-to-use layer is only implied by the tool's purpose.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All Marketplace Seller Fee Calculator toolsInspect
Try in Browser
One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources